Fluid irradiator



June 27, 1939. M. J. DORCAS ET AL 2,163,574

FLUID IBRADIATOR Original Filed April 2, 1935 INVENTORS Mf/P/P/LL JDORCAS GEORGE c. .SUPPL 5 BYFRANK REMESCMJ}:

I2 J M ATTO R N EY Patented June 27, 1939 STATES PATENT OFFECE FLUID IRRADIATOR.

Original application April 2, 1935, Serial No.

Divided and this application September 18, 1937, Serial No. 164,464

16 Claims.

This is a division of application Serial No. 14,206 filed April 2, 1935.

This invention relates to apparatus for the irradiation of liquids with radiant energy and .more especially to the radiation of liquid foodstuffs, such for example as milk, with ultraviolet energy whereby an increase in vitamin content is secured. The radiation of such substances as milk with ultra-violet energy produces 1.; What is known as anti-rachitic activation and this activation is generally attributed to an increase in the vitamin content. However, the particular wave length of energy employed and the particular type of activation secured forms no l; part of the present invention since the apparatus may be employed with liquids of any type and with energy from any source.

An object of our invention is to devise an irradiator having a non-circular curved surface which shall give substantially uniform effective irradiation to all parts of the film of liquid being irradiated. Another object of our invention is to provide an irradiating device wherein uniform irradiation may be obtained on a surface of increased area. A further object of our invention is to provide an irradiator whereby separate bodies of liquids may be irradiated under exactly the same conditions. Another object of our invention is to provide an apparatus in which all parts in contact with the liquid being irradiated are removable as a unit for cleaning.

These and other objects of our invention will in part be evident and will in part be set forth in the following specification, having reference to the accompanying drawing, in which:

l is a top view of an irradiator illustrating one embodiment of our invention.

Fig. 2 is a diagrammatic view showing the method of laying out the shape of said shell.

ig. 3 is a vertical section taken on the line 3-3 of Fig. 1.

Fig. 4 is a cross-section of the upper portion of the film supporting shell taken on line 4-4 of Figure l.

It is now well known that irradiation of such liquid foodstuifs as milk with various types of energy is desirable for the purpose of antirachitic activation, sterilization, etc. The irradiation of milk with ultraviolet energy to produce 5U anti-rachitic activation is becoming of increasing commercial importance. Heretofore, the apparatus has been of relatively large size or of very small laboratory size. We have devised an apparatus which is particularly adapted for use in 55 small commercial installations or in large scale laboratory investigations, but it may also be used in larger installations.

It is well known that the laboratory investigations of the degree of activation of various liquids, such as whole milk, skim milk, whey, or concentrated milk, are tedious and difficult. One of the reasons why such evaluations of anti-rachitic potency are difficult is that the testing of such products must be carried out by biological assays. In comparing the potency of various fluids it is essential that the fluids be irradiated under exactly the same conditions, This is not easy for various reasons. One of these is the fact that some sources of ultra-violet energy do not emit such energy at an absolutely constant rate. Hence, it is desirable that the samples to be compared be irradiated simultaneously from the same source of energy. We have devised an apparatus which permits of such irradiation.

In any irradiation of food products, and especially of dairy products, it is necessary that the devices used in treating them be cleaned frequently. It is well known that such products are subject to spoilage due to souring, etc. This is due to the presence of bacteria. this reason, among others, the apparatus must be thoroughly cleaned frequently. We have devised an apparatus in which the parts contacting with the irradiated liquid can be readily removed for frequent cleanings. Moreover all parts in contact with milk are removed as a unit and may be taken to a trough or the like for cleaning. This is an added convenience and reduces the danger of water coming in contact with the mechanism for producing ultra-violet energy.

In the embodiment of our invention illustrated in the accompanying drawing we have shown an arc lamp as the source of energy. While we have found an arc lamp using carbon electrodes with suitable flame materials in the core to be the best source of irradiation, our invention is not limited to such a source. In the drawing, there is shown an arc lamp A having electrodes E and driven by suitable conventional apparatus contained in a housing H. The housing is secured toa frame work P which is formed in any suitable manner, as by substantially vertical angle member it] and substantially horizontal angle members ii. The frame work may rest on any surface, such as the floor of the room in which the irradiation is being carried out, In order that it may be secured thereto, if desired, suitable members G2 are provided at the foot of the vertical member it. The vertical members Ill are preferably arranged at the corners of a rectangle. 55

2 reams The are lamp with its housing H is mounted at one of the shorter sicee of the rectangle. Opposite to the arc lamp housing there is provided a plate i i, since we prefer not to utilize this side of the de e for irradiation purposes. However, it is within scope of our invention to arrange the vertical members id at the corners of a square, pentagon, hexagon, etc. in which case three, four, five or more irradiating shells or screens would be provided instead or" the two shown in Fig. 1.

Sn the two longer sides of rectangle are arranged irradiating shells sz s. The shell consists of a vertical film suppoi lng surface 55, an upper trough ill and a lower receiving trough 8. The film supporting surface is curved as is shown in Fig. and as will be described more in detail hereinafter. The upper and lower troughs ii and i3 conform to the curvature of the film supporting surface. lower trough i8 is provided with outlet 5? The upper trough l! is divided in two portions and 2 5 by a vertical partition or bafile 2!! which is substantially parallel with the film supporting surface l5. The outer portion is provided with an inlet 23. The inner portion is provided with a slit 25 extending through the film sup porting surface it. The purpose of this slit is to supply milk evenly to the film supporting surface It is described more in detail and claimed in our oo-pending application Serial No. 14,206 filed April 2, 1935.

In the operation of the device the liquid to be irradiated, as for example milk, enters the outer portion 22 of the trough ll through the inlet 23. The milk is evenly distributed in the outer portion of the trough and flows over the baffle 2i into the inner portion 2 3. It then flows through the slit and down the film supporting surface it and is collected in the trough it from which it is removed through the outlet 59. In ordinary operations under commercial conditions the two inlets of the troughs would be connected and the outlets of the lower troughs of the separate shells would be connected. However, in case it is desired to conduct comparison tests on different liquids, one liquid would be introduced into the trough of one shell and the other liquid would be introduced into the trough of the other shell. In this case the irradiated liquids would of course be kept separate. By this means it is possible to irradiate different liquids under absolutely the same conditions for the purposes of comparison.

As shown above, the provision of two or more shells is of considerable advantage in case the irradiator is used in the laboratory. The same construction gives manifold advantages in commercial installations. The shells constituting the irradiating surface and the troughs can be removed for cleaning or other purposes. This is of especial importance in case the apparatus is used for irradiating milk. It is Well known that extreme cleanliness is required in all dairy operations, since undesirable flavor and odor changes would soon occur if bacteria were given an opportunity to develop. The simple provisions for the disassembly of the device is of marked importance in commercial as well as laboratory operations. Moreover, the demand for irradiated milk is subject to fluctuation. Milk is a perishable commodity and the irradiated milk cannot be stored for long periods of time. Accordingly it is desirable to have a device which will permit of some alteration in capacity and this without change in the operating characteristics. By using only one irradiating shell the capacity of the device may be cut in half and the operating conditions will be absolutely unchanged. Of course in case of an irradiator having more than two screens the variation in capacity would be even greater. In the past it has been possible to operate known irradiators at varying capacity only by disturbing predetermined film characteristics.

Furthermore, from a manufacturing standpoint the construction ofiers advantages. In case a customer desires an irradiator of a smaller capacity than that of the standard unit it is possible to ship him an irradiator having only one shell and with a blank sheet to occupy the position normally occupied by the other shell. The construction would be the same throughout and in case the customer eventually desired increased capacity it would only be necessary to provide him with the second shell which could readily be placed in position upon the removal of the blank sheet.

If still smaller units are desired for comparing the treatment of different liquids, each shell may be divided into two or more sections by providing bafiies to separate the troughs I? and it into sec- M tions, different liquids may be irradiated at the same time on each section of the shell.

The shells are secured to the frame F by studs 25 and 26 on the vertical angle members id. The stud 26 is adjustable in the slot 32 and the studs 25 and 26 engage slots in the vertical members 3d of the screen. Members all are provided at the bottom of the screen for tilting the irradiation shell about an axis passing through the upper surface of the studs 25 and 2'6.

The particular adjusting means are shown more in detail and claimed in the parent application above referred to.

For normal impingement, maximum efficiencies of irradiation are secured when the same intensity of energy is applied to each unit of surface of the film being irradiated. This is because it has been determined that certain intensities or periods of irradiation are most efiicient and an endeavor is made to irradiate each portion of the film at this intensity and for this period. Irradiating a portion of the liquid for a greater period and a portion for a shorter period, thus giving the same average period is not as satisfactory. For one thing the rate of activation decreases rapidly after the period of maximum efiiciency is passed. Hence, the over-irradiated liquid does not have an increased activation sufficient to compensate the under-irradiated liquid. Moreover, excess irradiation may cause undesirable changes, such as an undesirable odor or taste, or may even re sult in decreased activation. Similarly applying the radiant energy with uneven intensity upon the film surface results in decreased efficiencies with normal impingement. In order to obtain maximum efficiency it is desirable to irradiate the entire surface of the film as uniformly as possible. Where circumstances permit, this can be done by having the milk flow over the interior surface of a circular cylinder with the source of energy at the center. However, it is often inconvenient or impossible to use such a surface because of the size of the arc lamp. In such cases it is preferred to shape the surface as hereinafter described to give substantially uniform effective irradiation throughout a larger arc of the surface.

It is known that the intensity of irradiation upon a surface normal to the direction of radiation varies inversely asthe square of the distance from the source. It is also known that when the surface is inclined the intensity of the irradiation varies as the cosine of theangle of incidence. Furthermore, the effective utilization of the incident irradiation varies with the angle-of impingement of the rays, oblique irradiation favoring the enhancement of anti-rachitio effectiveness-without excessive undesirable effects upon odor and flavor. By taking advantage of these factors it is possible to obtain substantially uniform effective irradiation upon surfaces at varying distances from the source of energy in the same horizontal plane. Such an effect is secured in the device disclosed in our application. In Fig. 2 we show details of the development of a surface for an irradiator screen designed to secure such results. Fig. 2 represents diagrammatically a cross section through the center of the-arc lamp and one of the irradiator shells. The point 0 corresponds to the center of the energy source, i. e. the point of maximum intensity of the arc. A plurality of equal angles are laid off by lines passing through this point. These angles should be as small as convenient, but we have found that angles of 5 degrees give a contour of the section of the irradiator shell which is satisfactory. A distance L is laid off between two of the lines having an angle A between them. Ordinarily this would be laid off from the line which is to be the center line of the surface. An rc is drawn with radius L which will in sect the next adjoining line. Ordinarily this are will intersect this line in two points, in which case the point nearest 0 is employed. The distance L should be slightly greater than the chord between two adjacent 5 degree radii. From 1 point, where intersects the adjacent line, an equal distance L is laid off intersecting the next line. This is continued around until a contour has been developed sufficiently large for the purpose desired. We have found that by using the angle as 5 degrees that good results are obtained when eight such 5 degree angles are laid off on either side of the center line. points thus "lined are connected by a smooth curve and l determines the contour of the cross section of adlator shell.

.th such a contour the angle of impingement of the incident rays increases as the surface approaches the source of the rays, thus compeneating fo ncreased intensity and resulting in a su tanti y uniform effective irradiation. While it m y true that the energy intensity on every on of this in is not absolutely uniform yet W8 have found that by using the angle A equal to grees the departure of the intensity from the average is not sufliciently great to cause unfavorable irradiation conditions. In case such conditicns were produced, we would of course make the angle A smaller than 5 degrees. As a matter of fact the use of a smooth curve instead of a plurality of straight lines connecting the points as determined as above set forth tends to make the conditions approach more nearly the theoretical shape in which uniform effective irradiation condi one are present.

Thus it will be observed that we have secured an irradiation device in which we have compensated. for the fact that, under certain conditions,

. it is impossible to place the source of illumination being irradiated. We have also provided an irradiating device which has means for insuring an even flow of liquid over the irradiating screens or surfaces and which may be easily disassembled for thorough cleaning and accurately reassembled to insure uniform flow. Wehave also provided a device which is very accurate in comparing. the effects of. uniform radiation upon samples of different materials. While we have disclosed one type of apparatus suitable for securing these and other novel features-we do not wish our invention to belimited to this exact embodiment, as various modifications therein will readily occur to those skilled in the art.

We claim:

1. A liquid-treating apparatus comprising, in combination, a continuous surface of non-circular curvature adapted to support a film of liquid flowing thereover, and a source of radiant energy located substantially on an axis of said surface; said axis being spaced from said surface, andsurface being so shaped that radial lines in any plane perpendicular to said axis and forming equal angles at said axis intercept equal segments of the line of intersection of such surface with such plane, and the distance from said axis to said line along said radial lines decreasing with increasing obliqueness of said radial lines to said line.

2. An apparatus as defined in claim 1, including a plurality of separate irradiating surfaces, each of which is shaped and located about said source of radiant energy as defined therein.

3. An irradiating apparatus comprising, in combination, a continuous surface of non-circular cross section adapted to sup-port a film of liquid flowing thereover, and a source of radiant energy located substantially on an axis of said surface; said axis being spaced from said surface.

and said surface being so shaped that planes intersecting at said axis and forming equal clihedral angles at said axis intercept equal areas of said surface; the distance from said axis to said surface decreasing with increasing obliqueness of said planes to said surface.

4. An irradiating apparatus comprising, in combination, a source of radiant energy, means forming a continuous, substantially right cylindrically shaped surface of non-circular cross section adapted for flow of liquid to be irradiated and for supporting a film of said liquid, and means for positioning said surface where liquid supported by said surface may receive energy from said source; said source being located substantially at an axis of said surface and said surface being so shaped about said axis that radial lines in a plane normal to said axis and forming equal central angles at said axis subtend equal arcs of said surface; the distance from. said axis to said surface along said radial lines decreasing with increasing obliqueness of said radial lines to said surface, and the total central angle subtended at said axis by said radial lines being about 80 degrees.

5. A support for liquid film, which support comprises a shell forming a continuous, substantially right cylindrically shaped surface of non circular cross section adapted for flow of liquid axially thereover and for supporting a film of said liquid, said surface being so shaped that planes intersecting in a common line and forming equal dihedral angles at said common line of intersection intercept equal areas of said surface,

said line being an axis of said surface and spaced.

from said surface and the distance between said surface and said axis decreasing with increasing obliqueness of said planes to said surface; such shape of said surface and such spacing of said axis from said surface permitting a film of liquid supported by said surface to be given substantially uniform effective irradiation by radiant energy from a source located substantially on said axis.

6. A support for liquid film, said support comprising a shell forming a continuous, right cylindrically shaped surface of non-circular cross section adapted for the flow of liquid axially thereover and for supporting a film of said liquid, said surface being so shaped that planes intersecting at a common line and forming equal dihedral angles at said common line of intersection intercept equal areas of said surface, said line being an axis of said surface and spaced from said surface and the distance between said surface and said axis decreasing with increasing obliqueness of said planes to said surface; said surface subtending at said axis a total central dihedral angle of about 80 degrees; and such shape of said surface and such spacing of said axis from said surface permitting a film, of liquid supported by said surface to be given substantially uniform effective irradiation by radiant energy from a source located substantially on said axis.

7. An irradiating apparatus comprising, in combination, a source of energy, means forming a continuous, substantially right cylindrically shaped surface of non-circular cross section for support of liquid to be irradiated and means for positioning said surface where liquid supported by said surface may receive energy from said source, said surface being so shaped that planes intersecting at a common line and forming equal dihedral angles at said common line of intersection intercept equal areas of said surfaces, said line being an axis of said surface and spaced from said surface and the distance between said surface and said axis decreasing with increasing oblique ness of said planes to said surface; such shape of said surface and such spacing of said axis from said surface permitting a film of liquid supported by said surface to be given substantially uniform effective irradiation by radiant energy from a source located substantially on said axis.

8. An irradiating apparatus comprising, in combination, a source of energy, means forming a continuous, substantially right cylindrically shaped surface of non-circular cross section for support of liquid to be irradiated and means for positioning said surface where liquid. supported by said surface may receive energy from said source, said surface being so shaped that planes intersecting in a common line and forming equal dihedral angles at said common line of intersection intercept equal areas of said surface, said line being an axis of said surface and spaced from said surface and the distance between said surface and said axis decreasing with increasing obliqueness of said planes to said surface; said surface subtending at said axis a total central dihedral angle of about 80 degrees; and such shape of said surface and such spacing of said axis from said surface permitting a film of liquid supported by said surface to be given substantially uniform effective irradiation by radiant energy from a source located substantially on said axis.

9. The process of irradiating liquid which corn-- prises the steps of forming a film of flowing liquid having a continuous, substantially right cylindrically shaped surface of non-circular cross sec tion, and imparting to said film a substantially uniform effective irradiation from a source of radiant energy located substantially on an axis of said surface, said axis being so spaced from said surface and said surface being soshaped relative to said axis that planes intersecting at said axis and forming equal dihedral angles intercept equal areas of said surface, the distance from said axis to said surface decreasing with increasing obliqueness of said planes to said surface.

lO. The process of irradiating liquid which comprises the steps of forming a film of flowing liquid having a continuous, substantially right cylindrically shaped surface of non-circular cross section, and imparting to said film a substantially uniform effective irradiation from a source of radiant energy located substantially on an axis of said surface, said axis being so spaced from said surface and said surface being so shaped relative to said axis that planes intersecting at said axis and forming equal dihedral angles intercept equal areas of said surface, the distance from said axis to said surface decreasing with increasing obliqueness of said planes to said surface; and said surface subtending at said axis total central dihedral angle of about 80 degrees.

11. In an irradiating apparatus, a combination of a source of radiant energy, means forming a surface for a liquid to be irradiated and means for positioning said surface where it may receive radiant energy from said source; said surface being a non-circular right cylinder having a cross section such that, if lines be drawn from said light source in a plane normal to an axis of said cylinder and subtending equal angles at said source, equal arcs will be subtended on said surface by said lines, and the distance from said source to said surface along said lines will decrease with increasing obliqueness of said lines to said surface.

12. An apparatus as defined in claim 11, including a plurality of separate irradiating surfaces, each of which is shaped and located about said source of radiant energy as defined therein.

13. Apparatus as defined in claim 11, in which the surface is substantially vertical.

14. A support for liquid film, which support comprises a shell forming a continuous, substantially right cylindrically shaped surface adapted for flow of liquid axially thereover and for supporting a film of said liquid, said surface being so shaped that radial lines in any plane perpendicular to an axis of said surface and forming equal angles at said axis intercept equal segments of the line of intersection of such surface with said plane, the distance from said axis to said line along said radial lines decreasing with increasing obliqueness of said radial lines to said line.

15. The process of irradiating liquid which comprises the steps of forming a film of flowing liquid having a continuous, substantially right cylindrically shaped surface of non-circular cross section, and imparting to said film a substantially uniform effective irradiation from a source of radiant energy located substantially on an axis of said surface, said axis being so spaced from said surface and said surface being so shaped relative to said axis that radial lines in any plane perpendicular to said axis and forming equal angles at said axis intercept equal segments of the line of intersection of said surface with such plane, the distance from said axis to said line each of which is shaped and located about said along said radial lines decreasing with increasing source of radiant energy as defined therein. obliqueness of said radial lines to said line. FRANK REMESCH, J R. 16. An apparatus as defined in claim 3, includ- GEORGE C. SUPPLEE. 5 ing a plurality of separate irradiating surfaces, MERRILL J. DO-RCAS. 5

CERTIFICATE OF CORRECTION.

.Patent No. 2,165,57u. June 27, 19 9.

MERRILL J. DORCAS, ET AL.

It is' hereby certified that error appears in the printed specification of the above mnnbere'd patent requiring correction as follows: Page 2, first column, line 22, for the word "in" read into; page first column, line 11,0, claim'?, for "surfaces" read surface; inthe drawing, Figure L for the "25" designating the slit read 25 and that the said reference I numeral e read with this correction therein that the same Letters Patent should b may conform to the record oi the case in the Patent Office.

Signed and sealed this l2th day of September, A.D. 1959.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

